Externalities, entry bias, and optimal subsidy policy for cleaner environment

This paper analyses alternative subsidy schemes and long-run entry bias in a new industry that creates positive environmental externalities (both generation externalities and externalities associated with interindustry technology spillovers). It demonstrates that per-unit subsidy scheme, despite attracting fewer firms, results in higher industry output and economic surplus in the equilibrium compared with the expenditure equivalent lump-sum subsidy scheme. However, the later leads to higher total surplus, unless spillover externalities are sufficiently small. Further, the free-entry equilibrium number of firms may be excessive or insufficient. A key finding of this paper is that the first-best equilibrium outcome can be implemented through a unique combination of per-unit subsidy and lump-sum subsidy/tax, which involves positive government expenditure in the presence of positive externalities.